package com.pinyoumei.utils;

import java.util.List;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.pinyoumei.pojo.TbItem;

/**
 * 淘淘商城自定义响应结构
 */
public class JsonUtils {

    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
    	try {
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
    	return null;
    }
    
    /**
     * 将json结果集转化为对象
     * 
     * @param jsonData json数据
     * @param clazz 对象中的object类型
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
        	e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 将json数据转换成pojo对象list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
    	JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
    	try {
    		List<T> list = MAPPER.readValue(jsonData, javaType);
    		return list;
		} catch (Exception e) {
			e.printStackTrace();
		}
    	
    	return null;
    }
    
    public static void main(String[] args) throws Exception{
	
//	String str="[{\"id\":\"J_4872066\",\"p\":\"2799.00\",\"m\":\"2799.01\",\"op\":\"2799.00\"},{\"id\":\"J_1057741\",\"p\":\"2198.00\",\"m\":\"5299.00\",\"op\":\"2198.00\"}]";
//	 ArrayNode arrayNode=(ArrayNode) MAPPER.readTree(str);
//         for(JsonNode node:arrayNode){
//             System.out.println(node.get("id").asText());
//         }
    	String listString="[]";
    	List<TbItem> list=jsonToList(listString,TbItem.class);
    	System.out.println(objectToJson(list));
    	TbItem item=new TbItem();
    	list.add(item);
    	TbItem item2=new TbItem();
    	list.add(item2);
    	
    }
}
